Department of Immunology, University of Pittsburgh School of Medicine, PA 15213, USA.
J Transl Med. 2010 Feb 18;8:17. doi: 10.1186/1479-5876-8-17.
Type-1 T cells are critical for effective anti-tumor immune responses. The recently discovered microRNAs (miRs) are a large family of small regulatory RNAs that control diverse aspects of cell function, including immune regulation. We identified miRs differentially regulated between type-1 and type-2 T cells, and determined how the expression of such miRs is regulated.
We performed miR microarray analyses on in vitro differentiated murine T helper type-1 (Th1) and T helper type-2 (Th2) cells to identify differentially expressed miRs. We used quantitative RT-PCR to confirm the differential expression levels. We also used WST-1, ELISA, and flow cytometry to evaluate the survival, function and phenotype of cells, respectively. We employed mice transgenic for the identified miRs to determine the biological impact of miR-17-92 expression in T cells.
Our initial miR microarray analyses revealed that the miR-17-92 cluster is one of the most significantly over-expressed miR in murine Th1 cells when compared with Th2 cells. RT-PCR confirmed that the miR-17-92 cluster expression was consistently higher in Th1 cells than Th2 cells. Disruption of the IL-4 signaling through either IL-4 neutralizing antibody or knockout of signal transducer and activator of transcription (STAT)6 reversed the miR-17-92 cluster suppression in Th2 cells. Furthermore, T cells from tumor bearing mice and glioma patients had decreased levels of miR-17-92 when compared with cells from non-tumor bearing counterparts. CD4+ T cells derived from miR-17-92 transgenic mice demonstrated superior type-1 phenotype with increased IFN-gamma production and very late antigen (VLA)-4 expression when compared with counterparts derived from wild type mice. Human Jurkat T cells ectopically expressing increased levels of miR-17-92 cluster members demonstrated increased IL-2 production and resistance to activation-induced cell death (AICD).
The type-2-skewing tumor microenvironment induces the down-regulation of miR-17-92 expression in T cells, thereby diminishing the persistence of tumor-specific T cells and tumor control. Genetic engineering of T cells to express miR-17-92 may represent a promising approach for cancer immunotherapy.
1 型 T 细胞对于有效的抗肿瘤免疫反应至关重要。最近发现的 microRNAs（miRs）是一大类小的调控 RNA，可控制细胞功能的多个方面，包括免疫调节。我们鉴定了 1 型和 2 型 T 细胞之间差异调节的 miRs，并确定了这些 miRs 的表达如何受到调节。
我们对体外分化的小鼠辅助性 T 细胞 1（Th1）和辅助性 T 细胞 2（Th2）进行了 miR 微阵列分析，以鉴定差异表达的 miRs。我们使用定量 RT-PCR 来确认差异表达水平。我们还分别使用 WST-1、ELISA 和流式细胞术来评估细胞的存活、功能和表型。我们使用鉴定的 miRs 的转基因小鼠来确定 T 细胞中 miR-17-92 表达的生物学影响。
我们的初始 miR 微阵列分析表明，与 Th2 细胞相比，miR-17-92 簇是小鼠 Th1 细胞中表达最显著上调的 miR 之一。RT-PCR 证实，Th1 细胞中 miR-17-92 簇的表达始终高于 Th2 细胞。通过 IL-4 中和抗体或信号转导和转录激活因子（STAT）6 敲除破坏 IL-4 信号，可逆转 Th2 细胞中 miR-17-92 簇的抑制。此外，与非肿瘤对照相比，来自肿瘤荷瘤小鼠和神经胶质瘤患者的 T 细胞的 miR-17-92 水平降低。与来自野生型小鼠的对照相比，源自 miR-17-92 转基因小鼠的 CD4+T 细胞表现出更好的 1 型表型，表现为 IFN-γ产生增加和非常迟抗原（VLA）-4 表达增加。过表达 miR-17-92 簇成员的人 Jurkat T 细胞表现出增加的 IL-2 产生和对激活诱导的细胞死亡（AICD）的抗性。
2 型偏倚的肿瘤微环境诱导 T 细胞中 miR-17-92 表达的下调，从而减少肿瘤特异性 T 细胞的持久性和肿瘤控制。遗传工程改造 T 细胞表达 miR-17-92 可能是癌症免疫治疗的一种有前途的方法。
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